Dropping items as a spectator outside of the region forces the player to leave. Thanks to ACStache.

src/com/garbagemule/MobArena/ArenaListener.java

@@ -620,8 +620,7 @@ public class ArenaListener
     public void onPlayerDropItem(PlayerDropItemEvent event) {
         Player p = event.getPlayer();
 
-        // If the player is active in the arena, only cancel if sharing is not
-        // allowed
+        // If the player is active in the arena, only cancel if sharing is not allowed
         if (arena.inArena(p)) {
             if (!canShare) {
                 Messenger.tellPlayer(p, Msg.LOBBY_DROP_ITEM);
@@ -629,12 +628,24 @@ public class ArenaListener
             }
         }
         
-        // Else, if the player is in the lobby or a spectator, just cancel
-        else if (arena.inLobby(p) || arena.inSpec(p)) {
+        // If the player is in the lobby, just cancel
+        else if (arena.inLobby(p)) {
             Messenger.tellPlayer(p, Msg.LOBBY_DROP_ITEM);
             event.setCancelled(true);
         }
         
+        // Same if it's a spectator, but...
+        else if (arena.inSpec(p)) {
+            Messenger.tellPlayer(p, Msg.LOBBY_DROP_ITEM);
+            event.setCancelled(true);
+            
+            // If the spectator isn't in the region, force them to leave
+            if (!region.contains(p.getLocation())) {
+                Messenger.tellPlayer(p, Msg.MISC_MA_LEAVE_REMINDER);
+                arena.playerLeave(p);
+            }
+        }
+
         /*
          * If the player is not in the arena in any way (as arena player, lobby
          * player or a spectator), but they -are- in the region, it must mean

src/com/garbagemule/MobArena/Msg.java

@@ -67,6 +67,7 @@ public enum Msg
     MISC_HELP("For a list of commands, type /ma help"),
     MISC_MULTIPLE_MATCHES("Did you mean one of these commands?"),
     MISC_NO_MATCHES("Command not found. Type /ma help"),
+    MISC_MA_LEAVE_REMINDER("Remember to use /ma leave when you are done."),
     MISC_NONE("<none>");
     
     private String msg, spoutMsg;